1. Field of the Invention
The present invention relates to a circuit to be controlled, which is energized by a commercial power supply, a circuit with control function including a control means for controlling the circuit to be controlled, and a test method for examining whether or not the circuit with control function is normally operated.
2. Description of Related Art
There have been proposed various types of circuits with control function including a circuit to be controlled (hereinafter, referred to as a “controlled circuit”), which is energized by a commercial power supply and a control means for controlling the controlled circuit (see for example JP62(1987)-26455A and JP2(1990)-94383A).
JP '455 discloses a hot-air heater (corresponding to the circuit with control function) including a heater (corresponding to the controlled circuit) that is operated by a commercial power supply, a safety mechanism for stopping the operation in the event of a failure or trouble, a display means, a timer means, and a memory (corresponding to the control means). In this hot-air heater, the time at which the safety mechanism is activated is stored in the memory and, as the need arises, the display means displays the time of activation of the safety mechanism. Accordingly, the time of activation of the safety mechanism can be obtained even after the safety mechanism starts to operate. In maintenance or repair of the hot-air heater, therefore, an elapsed time from the start of activation of the safety mechanism and an operation period of time can be assumed, thereby enabling identification of the cause of failure or trouble.
JP '383 discloses an electric heater (corresponding to the circuit with control function) including a heat generator (corresponding to the controlled circuit) that is energized by a commercial power supply, an abnormality detection circuit for detecting a power supply voltage failure and a contact failure of a power supply switch, and a logic circuit (corresponding to the control means) for determining outputs of the abnormality detection circuit. In the event that a user erroneously connects a power plug to a high-voltage power supply or something is wrong with contacts having an operation switching function such as an operation changeover switch, the electric heater can inform the user of the abnormality in power supply voltage or the contact failure, e.g. adhesion, of the device at the start of energization but prior to the operation of the electric heater. Specifically, when the logic circuit detects any abnormality, an alarm is sounded to inform the user of the abnormality before the start of the operation of the electric heater. In the event of abnormality in power supply voltage, the operation is inhibited without closing the power supply switch. Thus, the abnormal use of the electric heater can be prevented to ensure safe operation thereof.
Meanwhile, another circuit with control function has also been proposed in which a circuit to be controlled (controlled circuit) such as a heater is operated only if a predetermined environment (e.g. ambient temperature) meets a specific condition (e.g. 0° or below). One of concrete examples is a circuit with control function provided with a heater (corresponding to the controlled circuit) which is energized by a commercial power supply to heat a secondary battery used as a power source of an electric vehicle or a hybrid electric vehicle. This circuit with control function is arranged to activate the heater (heating by energization) only under the condition that the ambient temperature is 0° or below for example to solve a problem in the secondary battery that cannot provide good output characteristics due to a decrease in discharge capacity under low-temperature environment (e.g. ambient temperature of 0° or below).
In the case where such circuit with control function is subjected to a completion test in a manufacturing facility or an operation check during actual use by the techniques disclosed in JP '455 and JP '383, a test environment for the circuit with control function has to be set in the specific condition (e.g. ambient temperature of 0° or below) in which the heater (controlled circuit) is caused to operate. This setting would require a larger testing system, leading to an increase in testing cost or cause difficulty in operation checks during actual use.